SPSSX Discussion

syntax for testing significant difference b/w two alphas

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Jims More

syntax for testing significant difference b/w two alphas

I got a syntax (pasted below) for testing a significant difference between two independent cronbach alphas.  However, it doesnot work.  I dont know the format of the input data.  Your suggestion is highly solicited. Jims

/* This program computes a test of the significance of the differences */.

/* between k independent coefficient alphas using a procedure described by */.

/* Hakstian & Whalen (1976).  The syntax is HWALPHA alpha n j, where alpha */.

/* is a variable in an SPSS file containing the k values of alpha, n is the */.

/* variable in the file containing the sample sizes, and j is the variable */.

/* containing the number of items in the measure */.

/* Written by Andrew F. Hayes */.

/* The Ohio State University */.

/* School of Journalism and Communication */.

/* [hidden email] */.

 

 

DEFINE HWALPHA (!positional !token(3)).

MATRIX.

get mat/variables = !1/missing = omit.

compute alpha = mat(:,1).

compute n=mat(:,2).

compute j=mat(:,3).

compute df = nrow(mat)-1.

compute a = ((j-1)&*((9*n-11)&**2))/((18*j)&*(n-1)).

compute top = a&*((1-alpha)&**(-1/3)).

compute bot = a&*((1-alpha)&**(-2/3)).

compute m = csum(a)-((csum(top)**2)/csum(bot)).

print/title = "** SIGNIFICANCE TEST OF THE DIFFERENCE BETWEEN INDEPENDENT ALPHA COEFFICIENTS **".

print/title = "From Hakstian & Whalen (1976), Psychometrika, 41, 219-231.".

print mat/clabels = "ALPHA" "N" "ITEMS"/title = " "/format F10.4.

compute p = 1-chicdf(m,df).

compute res = {m, df, p}.

print res/clabels = "CHISQ" "DF" "P-VALUE"/title = " "/format F10.4.

END MATRIX.

!END DEFINE.

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Mario Giesel

Re: syntax for testing significant difference b/w two alphas

Hello, Jims,
 
The last command should be "!ENDDEFINE." - without a blank?!
 
Good luck,
Mario

Von: Jims More <[hidden email]>
An: [hidden email]
Gesendet: Samstag, den 21. Februar 2009, 23:12:08 Uhr
Betreff: syntax for testing significant difference b/w two alphas

I got a syntax (pasted below) for testing a significant difference between two independent cronbach alphas.  However, it doesnot work.  I dont know the format of the input data.  Your suggestion is highly solicited. Jims /* This program computes a test of the significance of the differences */.

/* between k independent coefficient alphas using a procedure described by */.

/* Hakstian & Whalen (1976).  The syntax is HWALPHA alpha n j, where alpha */.

/* is a variable in an SPSS file containing the k values of alpha, n is the */.

/* variable in the file containing the sample sizes, and j is the variable */.

/* containing the number of items in the measure */.

/* Written by Andrew F. Hayes */.

/* The Ohio State University */.

/* School of Journalism and Communication */.

/* [hidden email] */.

DEFINE HWALPHA (!positional !token(3)).

MATRIX.

get mat/variables = !1/missing = omit.

compute alpha = mat(:,1).

compute n=mat(:,2).

compute j=mat(:,3).

compute df = nrow(mat)-1.

compute a = ((j-1)&*((9*n-11)&**2))/((18*j)&*(n-1)).

compute top = a&*((1-alpha)&**(-1/3)).

compute bot = a&*((1-alpha)&**(-2/3)).

compute m = csum(a)-((csum(top)**2)/csum(bot)).

print/title = "** SIGNIFICANCE TEST OF THE DIFFERENCE BETWEEN INDEPENDENT ALPHA COEFFICIENTS **".

print/title = "From Hakstian & Whalen (1976), Psychometrika, 41, 219-231.".

print mat/clabels = "ALPHA" "N" "ITEMS"/title = " "/format F10.4.

compute p = 1-chicdf(m,df).

compute res = {m, df, p}.

print res/clabels = "CHISQ" "DF" "P-VALUE"/title = " "/format F10.4.

END MATRIX.

!END DEFINE.

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Mario Giesel
Munich, Germany

Art Kendall

Re: syntax for testing significant difference b/w two alphas

In reply to this post by Jims More

try this. replace the last line with this syntax.

if the original article has an example you might want to try it to verify the it works as you expect..
!ENDDEFINE. data list list /test(f1) myalpha(f4.3) samplesize(f5) n_items (f5). begin data 1 .981 101 13 2 .892 50 13 3 .855 25 13 4 .722 20 13 end data. hwalpha myalpha samplesize n_items.
Art Kendall
Social Research Consultants

Jims More wrote:

I got a syntax (pasted below) for testing a significant difference between two independent cronbach alphas.  However, it doesnot work.  I dont know the format of the input data.  Your suggestion is highly solicited. Jims

/* This program computes a test of the significance of the differences */.

/* between k independent coefficient alphas using a procedure described by */.

/* Hakstian & Whalen (1976).  The syntax is HWALPHA alpha n j, where alpha */.

/* is a variable in an SPSS file containing the k values of alpha, n is the */.

/* variable in the file containing the sample sizes, and j is the variable */.

/* containing the number of items in the measure */.

/* Written by Andrew F. Hayes */.

/* The Ohio State University */.

/* School of Journalism and Communication */.

/* [hidden email] */.





DEFINE HWALPHA (!positional !token(3)).

MATRIX.

get mat/variables = !1/missing = omit.

compute alpha = mat(:,1).

compute n=mat(:,2).

compute j=mat(:,3).

compute df = nrow(mat)-1.

compute a = ((j-1)&*((9*n-11)&**2))/((18*j)&*(n-1)).

compute top = a&*((1-alpha)&**(-1/3)).

compute bot = a&*((1-alpha)&**(-2/3)).

compute m = csum(a)-((csum(top)**2)/csum(bot)).

print/title = "** SIGNIFICANCE TEST OF THE DIFFERENCE BETWEEN INDEPENDENT ALPHA COEFFICIENTS **".

print/title = "From Hakstian & Whalen (1976), Psychometrika, 41, 219-231.".

print mat/clabels = "ALPHA" "N" "ITEMS"/title = " "/format F10.4.

compute p = 1-chicdf(m,df).

compute res = {m, df, p}.

print res/clabels = "CHISQ" "DF" "P-VALUE"/title = " "/format F10.4.

END MATRIX.

!END DEFINE.

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Art Kendall
Social Research Consultants

mphilramesh

Re: syntax for testing significant difference b/w two alphas

In reply to this post by Jims More

Hi,

Please send the SPSS syntax of the covariate meta-analysis...

Jims More wrote

I got a syntax (pasted below) for testing a significant difference between two independent cronbach alphas. However, it doesnot work. I dont know the format of the input data. Your suggestion is highly solicited. Jims /* This program computes a test of the significance of the differences */.

/* between k independent coefficient alphas using a procedure described by */.

/* Hakstian & Whalen (1976). The syntax is HWALPHA alpha n j, where alpha */.

/* is a variable in an SPSS file containing the k values of alpha, n is the */.

/* variable in the file containing the sample sizes, and j is the variable */.

/* containing the number of items in the measure */.

/* Written by Andrew F. Hayes */.

/* The Ohio State University */.

/* School of Journalism and Communication */.

/* [hidden email] */.

DEFINE HWALPHA (!positional !token(3)).

MATRIX.

get mat/variables = !1/missing = omit.

compute alpha = mat(:,1).

compute n=mat(:,2).

compute j=mat(:,3).

compute df = nrow(mat)-1.

compute a = ((j-1)&*((9*n-11)&**2))/((18*j)&*(n-1)).

compute top = a&*((1-alpha)&**(-1/3)).

compute bot = a&*((1-alpha)&**(-2/3)).

compute m = csum(a)-((csum(top)**2)/csum(bot)).

print/title = "** SIGNIFICANCE TEST OF THE DIFFERENCE BETWEEN INDEPENDENT ALPHA COEFFICIENTS **".

print/title = "From Hakstian & Whalen (1976), Psychometrika, 41, 219-231.".

print mat/clabels = "ALPHA" "N" "ITEMS"/title = " "/format F10.4.

compute p = 1-chicdf(m,df).

compute res = {m, df, p}.

print res/clabels = "CHISQ" "DF" "P-VALUE"/title = " "/format F10.4.

END MATRIX.

!END DEFINE.

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